Grinding.



can grains re CLARENCE ROSGOE KING, OF WORCESTER, MASSACHUSETTS, ASSIGNOR TO NORTON COMPANY, A CORPORATION OF MASSACHUSETTS.

Patented July 20, 1915..

GRINDING.

L146 88 Specification of Letters Patent.

No Drawing. Application filed January 26, 1914.

To all whom it may concern Be it known that I, CLARENCE Roscou KING, a citizen of the United States, residing at Worcester, in the county of Worcester and State of Massachusetts, have invented a new and useful Improvement in Grinding, of which the following is a specification.

Grinding is accomplished by applying an abrasive grinding surface to the material to be ground. Grinding is commonly done with wheels which are made up of particles of abrasive of an aluminous nature, such as alundum, corundum or emery; of silicon carbid, commonly called carborundum or crystolon, or of other hard material held together by some form of silicate binder, such as vitrified or fused clay, or other mineral mixture, or silicate of soda, commonly known as water glass. These grinding instrumentalities or wheels are porous. In use, the cutting action of the abrasive in the face of the grinding wheel becomes impaired, first, because .of glazing, that is, the abrasive particles lose their cutting edges and wear smooth; and second, because of loading or filling, that is, particles of the material being ground work into and more or less fill up the'voids in the face of the grinding wheel and cover up the cuttingedges of the particles of abrasive. This necessitates frequent reduction of the grinding face of the wheel with dressing tools or diamonds to obtain new cutting surfaces with a corresponding loss of time and wheel.

Attempts have been made to improve the action of grinding wheels by embodying a soft, lubricating substance, such as paraffin, vaseline or tallow in the voids thereof. While these ingredients have improved the cutting action of grinding wheels more or less, it has been difficult to make stable wheels this way because the parafiin, etc., will run out of the wheel, particularly when warm, and the wheel will get out of balance. Further, in the process of grinding, grease is apt to fly out by centrifugal action without accomplishing any function. Moreover, these compounds do not very materially prevent loading, they smoke badly, and they Serial No. 814,584.

cause the wheel to act softer. Attempts have also been made to use graphite or plumbago in grinding wheels without very much success.

As distinguished from these previous attempts, the present invention consists in embodying a filler of resin or resinous material in the voids of a porous grinding instrumentality or wheel, made up of abrasive particles held together by a binder.

To carry out the invention, the ordinary colophony resin or rosin is melted by heat and the ordinary porous vitrified grinding wheel is dipped therein so that the wheel absorbs a percentage of said resin which becomes embedded in the voids thereof upon cooling. The best results are obtained preferably by heating the wheel before dipping, to about the same temperature as the melted resin. Remarkable results are obtained with a wheel made this way. The effectiveness of cutting is improved, glazing is immaterial, and loading is greatly reduced and almost eliminated. The wheel will not get out of balance by the resin flowing because a resinous compound is solid and very viscous at normal temperatures. Under the heat of grinding, the resin on the grinding surface of the wheel becomes fluid and sticky and forms a sort of sticky film on the grinding surface. As the particles of metal, or of the material which is being ground, are cut ofi, this film seems to prevent the entrance of such particles into the voids in the wheel and the particles become embedded in this film, and as this film slightly hardens on leaving the point of grinding contact and becomes more or less brittle, the particles ,will fly off from the surface of the wheel a 1,1ee,ese

without glazing or loading than the same to form a porous, unitary structure, and havwheel without the resinous compound ing a filler of resinous material embedded in I therein. v the voids thereof. v r The resin or resinous compound mayv be In testimony whereof I have hereunto set 5 embedded in the voids of the porous wheel my hand, in the presence of two subs r g 15 in other ways from that which is herein dewitnesses. 1

scribed. CLARENCE ROSCOE KING What is claimed is Witnesses: A grinding instrumentality made up of LOUIS'W. SOUTHGATE,

10 abrasive particles held together by a binder C. FORREST WESSON. 

